"Congratulations to our mission partners at Orbital ATK and NASA on another successful launch that will help advance our scientific knowledge on Earth and in space, and inspire the next generation of space explorers", said Wentz. The OA-7 mission has been on hold for a month due to a technical issue with the rocket's first-stage hydraulics. Orbital has also experienced a failed mission.
"We are carrying more this time than we have in the past and that's a good step forward for us and for the crew", Frank Culbertson, president of Orbital ATK's Space Systems Group, told reporters during a pre-launch news conference. The Antares was grounded for two years after that while the vehicle's engines were replaced; the Atlas V served as a stopgap in the meantime so that Orbital could continue to resupply the station as part of its contractual obligations to NASA. The mission will deliver cargo to the International Space Station (ISS).
The next Cygnus flight, OA-8E, is planned for October 2017.
Research materials aboard the Cygnus include a plant growth chamber to test whether Space Station inhabitants could grow their own food during future extended stays aboard the station, and a drug company's test of a chemotherapy drug that targets cancer cells with antibodies, Floriday Today reported.
The capsule also is carrying 38 shoebox-size satellites called cubesats, four of which will remain on board the spacecraft and be deployed after it departs the station in July.
Once attached and leak checks between the hatches of the station and spacecraft are conducted, the crew will open the hatch and begin unloading the cargo and experiments. That's because a pair of astronauts are scheduled to launch early Thursday morning on a Russian Soyuz rocket. Cygnus consists of a common Service Module (SM) and a Pressurized Cargo Module (PCM).
Orbital ATK's seventh cargo delivery flight to the station launched at 11:11 a.m. EDT Tuesday on a United Launch Alliance Atlas V rocket from Space Launch Complex 41 on Cape Canaveral Air Force Station in Florida.
Forecasters on Monday predicted a 90 percent chance the weather would be suitable for launch on Tuesday.
Lifftoff is now scheduled for April 18 at 15:11 UTC (11:11 EDT), with NASA set to broadcast a world-first live 360-degree stream of the launch, viewable via NASA's YouTube channel.